Airfoil Dirt Separator for Film Cooling Hole Plugging
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Solution Overview
Problem
Turbine cooling holes in gas turbine engines are limited in size due to dirt plugging issues, leading to reduced part life and inefficiencies in heat transfer.
Innovation Solution
An internally cooled airfoil with a dirt filtering system, featuring interior protrusions that separate dirt from coolant air, allowing for smaller cooling holes and improved dirt removal, thereby enhancing coolant flow and heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If cooling holes are made smaller to improve heat transfer efficiency, then heat transfer efficiency is improved, but dirt plugging risk increases
Solution Approach 1:
The cooling system is segmented into multiple functional zones: a dirt separation zone with protrusions that intercepts and removes particles before coolant enters the cooling holes, and a cooling zone with optimized hole distribution. This segmentation allows small cooling holes to be used without direct exposure to dirt-laden coolant, resolving the contradiction between small hole size for heat transfer and dirt plugging resistance.
Solution Approach 2:
Protrusions into the cooling passages act as intermediary elements that separate dirt particles from the coolant flow before the coolant reaches the cooling holes. These protrusions create a pre-cleaning zone where particles are diverted, allowing the subsequent cooling holes to operate without direct particle exposure, thus enabling smaller hole sizes while maintaining reliability.
2Reliability
If cooling holes are made larger to prevent dirt plugging, then dirt plugging resistance is improved, but heat transfer efficiency decreases
Solution Approach 1:
The cooling system is segmented into multiple functional zones: a dirt separation zone with protrusions that intercepts and removes particles before coolant enters the cooling holes, and a cooling zone with optimized hole distribution. This segmentation allows small cooling holes to be used without direct exposure to dirt-laden coolant, resolving the contradiction between small hole size for heat transfer and dirt plugging resistance.
Solution Approach 2:
Protrusions into the cooling passages act as intermediary elements that separate dirt particles from the coolant flow before the coolant reaches the cooling holes. These protrusions create a pre-cleaning zone where particles are diverted, allowing the subsequent cooling holes to operate without direct particle exposure, thus enabling smaller hole sizes while maintaining reliability.
3Use of energy by moving object
If trip strips are added to enhance convective heat transfer, then heat transfer efficiency is improved, but device complexity increases
Solution Approach 1:
The protrusions serve multiple functions simultaneously: they act as dirt separation elements by intercepting particles, and they serve as turbulence generators to enhance convective heat transfer. By merging the dirt separation function and heat transfer enhancement function into a single structural feature, the design avoids adding separate trip strips, thus improving heat transfer without proportionally increasing device complexity.
Solution Approach 2:
The protrusions into the cooling passages are designed to perform multiple functions: particle separation, turbulence generation for heat transfer enhancement, and potential flow direction control. This multi-functionality reduces the need for additional components, resolving the contradiction between heat transfer improvement and device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The dirt filtering system effectively prevents dirt plugging, enabling the use of smaller cooling holes and improving the airfoil's cooling efficiency and longevity by ensuring uninterrupted coolant flow and enhanced heat transfer.
Implementation Method 1
The slope of the first sloped surface and the slope of the second sloped surface are selected so that dirt particles within the first internal cooling passage are routed away from the first cooling hole
Implementation Method 2
Coolant flows through the serpentine to convectively cool the airfoil and discharges through the cooling holes to provide film cooling
Data Source
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AI summary
A gas turbine engine internally cooled component airfoil (400) having a peripheral wall having an external surface comprising a suction surface and a pressure surface laterally spaced from the suction surface, including a cooling system having at least one or more passages including a first passage pressure side surface that includes an interior protrusion (412), the geometry of which providing a dirt filtering system. The interior protrusion includes a first sloped surface (414) extending to a peak of the interior protrusion and a second sloped surface (418) extending from the peak substantially in the direction of the pressure side surface with a slope that is greater than the slope of the first sloped surface. A first cooling hole (404) extends from the second sloped surface through the interior protrusion to vent the first of the one or more passages to the pressure side surface.